Conference Room Router – Why?

DSP programming for teleconference rooms is complicated by the fact that there are multiple types of signals that all need to be processed independently. Routing the wrong input signals to an output can cause

•   echoes on the far-end.
•   echoes on the near-end.
•   some participants being inaudible.
•   microphones that sound like they are “under water”.

A teleconference room has clear, straightforward routing requirements. Each of these requirements must be met correctly for a teleconference room to function properly. When executing these simple rules, the big question is, who has the responsibility of executing all the routing rules correctly?

One very common method of programming DSPs for teleconferencing is to place a large matrix mixer in the file. This is a favorite method of DSP programmers because everything and anything is possible with this design. The programmer does not need to worry about how the room will work, or where the audio signals need to be routed. All responsibility for proper routing of audio will be passed off to the installation staff.

The matrix mixer in this example will have 195 crosspoints. Only 126 of those crosspoints are required for the proper functioning of the teleconference room. The remaining crosspoints will never be used and many of them will cause serious problems if they are used.

There are 60 crosspoints that should never be turned on; enabling these crosspoints will immediately cause echo either on the far-end or the near-end.

An additional 4 crosspoints need to be turned on and should never be turned off; disabling these crosspoints will cause echo on the far-end.

There are 9 crosspoints that will cause distortion of the local microphones if they are turned on. This distortion is often described as the mics sounding like they are “under water”. A microphone signal should never be routed to its own AEC reference, but the large matrix mixer provides nine different crosspoints that will do exactly that.

Rather than use a single, large matrix, the programmer could elect to use individual mixers for each type of output. Each mixer is dedicated to one type of output and receives only the signals that are appropriate for that type of output. Using this method, there is no possibility of routing the wrong signals to an output. Unfortunately, this method also has problems:

  • This is a more complicated design for the DSP programmer
  • The wiring is more complex in the project file and requires much more screen space.
  • Adjusting levels and configuring this system onsite requires adjustments on multiple control panels.
  • The Crestron/AMX programmer must control multiple mixers.
  • There is no master volume when using this method.

The Bose ControlSpace® Conference Room Router provides a single object that can be quickly added to a design file and can be configured by the installation staff safely and easily when setting up the room. The Conference Room Router also prevents the creation of any dangerous crosspoints, thereby eliminating the possibility of their accidental use.

The Conference Room Router is a composite object containing three interconnected matricies, which provide all of the crosspoints needed to configure the system without including any of the crosspoints that would cause problems if they  were configured incorrectly. 

Configuring a Conference Room Router with the appropriate inputs and outputs to match the needs of each project is easily accomplished by selecting the appropriate quantity of each type of input and output in the Conference Room Router Wizard. When the Conference Room Router Wizard is closed, the Conference Room Router is configured with the selected inputs and outputs. If an existing Conference Room Router needs to be modified, the Conference Room Router Wizard may be used at any time to change the number of inputs and outputs on the Conference Room Router. A Conference Room Router may be configured, placed into the project, and wired to the input and output processing in just a few minutes.